The principal limitation to understanding the mechanism of redox regulation is the lack of information on the identity of redox proteins that regulate cellular processes and on the specific functions of these proteins. We propose to develop and employ bioinformatics tools for identification of redox proteins of the thiol/disulfide oxidoreductase family, and subsequently predict functions of these proteins through experimental and computational analyses. The following questions will be addressed: (1) Can disulfide oxidoreductases be identified by searching for redox motifs within conserved secondary structure patterns? We will develop computer programs capable of identifying disulfide oxidoreductases. (2) What is the number of disulfide oxidoreductases in completely sequenced genomes? The majority of disulfide oxidoreductases will be identified in completely sequenced genomes, including the human genome. (3) What are the intracellular localization and expression patterns of the disulfide oxidoreductases? Sequences for identified mammalian proteins will be verified and expression, subcellular localization and interacting partners will be determined for ~30 mouse proteins. (4) What are functions of disulfide oxidoreductases? Bioinformatics analyses and experimental data will be used to predict protein functions. A web-based database of disulfide oxidoreductases will be developed. Preliminary data demonstrate feasibility of the proposed study.